A climate comparison is when climate data from two cities, regions or countries are placed against one another and compared. Such comparisons use modern technology and all available data to map local and national climate data. The information is used for planning trips, in agriculture and for investigating climate phenomena.
Climate is different from weather. The latter is a short-term combination of factors including temperature, air pressure and cloud activity. Climate is a more long-term model based on accumulated weather data. The data can be spread over weeks, months or years. It can also use information from decades and centuries.
A common use of a climate comparison is to plan vacations and holidays. The simplest data used is average temperature. For example, if a family from Austin in Texas wants to choose somewhere on the East Coast of America to go on vacation, it can compare average temperatures of cities such as Charleston and Atlanta.
In order to accumulate the data, scientists take temperature recordings each day. These readings will be at a specific time of day. They then take the readings, for example for 20 May, of each year since readings were first taken. The average then tells the prospective visitor the average temperature on 20 May. The same can be done for specific weeks or months of the year.
More complex forms of climate comparison involve additional data. Archaeologists across the world gather data from tree rings. The results are extremely localized, as it depends on the weather experienced by that one tree. If the year is warm, then the ring will be thick, and if the year is cold, then the ring will be thin. Tree ring cores form climate chronologies by matching data of trees of different ages.
Other climate comparison techniques include crop yields. These are also localized, as they depend on soil quality. Farmers use climate information to help them know when and where to plant their crops.
The amount of climate comparison data available increased exponentially during the 20th century. This coincided with the development of computer systems and investigations into Earth’s climate history. Computer modeling and data processing has led not only to histories of Earth’s climate, but also to predictions for the future.
The amount of climate data available to scientists shows how complex the world’s climate system is. It is a dynamic system combining currents, the moon, Earth activity and more. The data is often highly localized and is often contradictory. Climate comparison data has been used to prove global warming, but also to disprove it.